1. Field of the Invention
The present invention relates to a squeeze for a screen printer, and more particularly to a squeeze for a screen printer capable of preventing a dog ear phenomenon that an adhesive paste is asymmetrically formed in an indented shape when an etching portion of a metal mask is coated with the adhesive paste to mount chip parts in a manufacturing process of BOC (Board on chip).
2. Description of the Related Art
BOC (Board on chip) is a substrate for a next-generation high-speed semiconductor capable of minimizing losses of thermal and electrical performances in a high-speed D-RAM semiconductor using a process for directly mounting a semiconductor to a printed circuit board rather than a substrate using a lead frame. This BOC (Board on chip) is manufactured by coating a printed circuit board with an adhesive paste, putting chip parts on the adhesive paste printed at a suitable thickness, and then attaching the chip parts to the printed circuit board by means of a heating process.
The coating of the printed circuit board with the adhesive paste is carried out using a conventional screen printer. Hereinafter, a coating procedure with the adhesive paste using a screen printer is described in detail with reference to FIG. 1.
Firstly, a printed circuit board 3 is laminated on a supporter 1, and a metal mask 5 having an opening formed therein is formed on the printed circuit board 3. Subsequently, an adhesive paste 7 is scattered on the metal mask 5, and then a screen printer is operated. In this procedure, the printed circuit board that remains open through the opening of the metal mask 5 is coated with the adhesive paste 7 by pushing the adhesive paste 7 into the opening of the metal mask 5 while a squeeze for a screen printer 100 moves parallel over the metal mask 5.
However, the adhesive paste 7 is attached to the squeeze 100 in the coating process of the adhesive paste 7, and therefore a layer of the adhesive paste 7 is asymmetrically formed in an indented manner, as shown in “A” of FIG. 2. This phenomenon is referred to as a dog ear, which deteriorates adhesion of the chip parts to the printed circuit board and damages stability of the chip parts, resulting in a deteriorated performances of electronic products.
There have been ardent attempts to solve the above problems in the related art, and therefore the present invention was designed based on the above-mentioned facts.